L-Theanine
Of 1,997 on-market l-theanine products in the January 2026 DSLD dump, the median declared dose is 100 mg, and 100.0% list L-Theanine (generic/unbranded) as the primary form.
Form share
Of 1,997 products with an identifiable primary form, here is the share held by each form of L-Theanine on the market today.
| Form | Quality tier | n | Share |
|---|---|---|---|
| L-Theanine (generic/unbranded) | Tier 2 | 1,997 | 100.0% |
Form share over time
Entry-year breakdown of the top forms, 2012–2025.
Dose distribution
Deciles of declared dose per serving (mg), among 1,492 products with a disclosed amount.
- 1.1% of products fall below the fairy-dust threshold (10 mg, 20% of the studied low dose).
- 25.1% of products don't disclose an amount because L-Theanine is declared inside a proprietary blend.
By dosage form
By target group
Top brands
Forms explained
Chemically identical to branded forms when purity is verified, but some generic products have tested as racemic (D/L) mixtures rather than pure L-isomer -- quality is manufacturer-dependent, not guaranteed by the name alone.
Source: purity/isomer distinction discussed in industry comparative literature -- independent verification recommended
The specific branded ingredient used in the large majority of published human L-theanine RCTs, giving it the deepest clinical evidence trail of any single commercial form; independent analyses report >99% L-isomer purity. Superiority to a verified-pure generic is not independently confirmed by a head-to-head PK/outcomes trial -- this tier reflects depth of clinical usage, not proven PK superiority.
Source: widely used as the study article across L-theanine RCTs; purity claim is manufacturer-sourced
No independent human clinical trials specific to this branded form were found.
Source: uncertain -- needs review
Reference values
- RDA (adult): not established — Non-proteinogenic amino acid found in tea; no DRI exists.
- Tolerable Upper Intake Level (adult): not established — Not established. FDA has granted L-theanine GRAS status for food/beverage use, which speaks to food-level safety, not a UL determination.
- Studied clinical dose range: 50–200 mg
- Lu K et al. 2004, Hum Psychopharmacol 19(7):457-65, PMID 15378679 -- RCT (n=16) crossover, 200mg L-theanine vs 1mg alprazolam vs placebo; L-theanine did not reduce anxiety under an acute anticipatory-anxiety condition (unlike alprazolam) but showed relaxation-related effects under a resting condition.
- Note: Some generic/unbranded L-theanine has tested as a racemic (D/L) mixture rather than pure L-isomer in commercial testing; D-theanine is poorly absorbed/inactive relative to L-theanine, so purity is manufacturer-dependent rather than guaranteed by the name alone.